THE ESSENTIAL
- In patients infected with Covid-19, loss of smell does not result in a stuffy nose
- Loss of smell is problematic in the kitchen where 90% of activities are linked to odors
- Loss of smell is problematic in cooking where 90% of what we eat is related to odors
- Researchers test the effectiveness of nose washes with cortisone and olfactory rehabilitation to restore the taste of odors in those who have lost it
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Very soon, loss of smell appeared as one of the characteristic symptoms of a Covid-19 infection. It is even a pathognomonic symptom, that is to say a clinical sign which, by itself, makes it possible to establish the diagnosis. If anosmia is common in respiratory diseases, it is caused by the congestion of the nasal passages and a stuffy nose. In patients infected with SARS-CoV-2, the nose is not blocked.
Recently, researchers have successfully identified the mechanisms that lead to anosmia. Thanks to scanners, they observed that the olfactory slit, the part of the nose responsible for the perception of odors, becomes blocked by swelling of the soft tissues as well as by mucus, while the rest of the sinuses of the patients is normal, explaining why the nose is not blocked. The virus uses the ACE2 receptors to attach to and infect cells, yet these receptors are not expressed by olfactory neurons. These receptors are found on the surface of the sustentacular cells and their infection by the virus leads to an inflammation in the olfactory cleft, explaining the swelling of the tissues which obstructs the olfactory neurons and leads to the loss of smell.
“All alone under a glass bell”
This door to smell is a real handicap. “We discover smell when we lose it”, Confides to AFP Jean-Michel Maillard, president of the association Anosmie.org. All the little pleasures of life linked to odors suddenly disappear. “What I miss most is the smell of my sons when I kiss them, it is the smell of my wife’s body, the smell of my dad. Anosmia cuts you off from the smells of life, it’s a torture”, He testifies. One of the most problematic consequences related to anosmia is in the kitchen. Besides the loss of sensations when we eat or sniff the good smells of the pan, cooking becomes complicated since 90% of what we eat is related to smell.
In the case of the coronavirus, the loss of smell does not generally last over time. Majority of patients recover smell in just two weeks. In other cases, the anosmia can be much longer. “When people lose their sense of smell and there is no recovery, there is a real deterioration in the quality of life and a rate of depression that is not negligible at all ”, notes Alain Corré, ENT at the Rothschild Foundation Hospital in Paris. “It doesn’t matter if you don’t smell for a month. Two months, it’s starting to be embarrassing. After 6 months, you are all alone, under a glass bell, relates Jean-Michel Maillard. There is a very difficult psychological dimension to live with, you have to get help. ” In addition to Covid-19, other diseases can lead to loss of smell such as nasal polyposis, chronic rhinitis, diabetes, Alzheimer’s or Parkinson’s.
Olfactory rehabilitation
For the moment, there is no treatment to cure anosmia. “The problem with anosmias linked to the virus is that often the treatment of viral infection has no effect on smell”, Describes Dr. Corré. Olfactory neurons have a regenerative capacity which means that most people who have lost their sense of smell will eventually recover it. In the Parisian hospitals Rothschild and Lariboisière, a study “CovidORL”Was set up to test the effectiveness of nose washes with cortisone (budesonide), combined with olfactory rehabilitation, to help recover. Alain Corré thus advises: “choose five smells in your kitchen – that you like – like cinnamon, thyme, bay leaf … Breathe them twice a day, for 5 to 10 minutes, watching what you are breathing.”
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